The Alarm Box – Part II

I know this is supposed to be a weekend project, but I had some spare time on my Thursday evening So here an update on my vSphere Alarm Box.

I received my analog panel meters this week. Instead of them displaying 0 to 5v I created some new face plates for them using my automatic paper cutter so they can display CPU and Memory consumption. These meters are very easy to control by using a PWM signal, but the challenge is that the Raspberry PI only has one PWM port. So I decided I want to use an arduino for this. Making the Raspberry PI talk to the arduino is fairly straight foward. I am using I2C, but as the arduino uses 5v for its logic circuits and the Raspberry 3.3v I had to build a small level shifter to allow both both safely to communicate over I2C.

Everything now connected hardware wise, now I just had to make the meters work, displaying the right information from VC. I am writing my code in PHP and already had last weekend written the PHP code to use the QueryPerf API call to retrieve the last 5 minute average for CPU and memory of my cluster. But PHP does not allow me to send I2C calls, so I had to write an extension module for PHP to enable me to do this. As I never had written an PHP module, thanks to google, this did not take too long

So there it is.. IT IS WORKING Every minute Raspberry PI uses QueryPerf to retrieve information from VC. Using my PHP I2C extension it sends an I2C call, via the level shifter to my arduino. The arduino uses the value received via I2C to set the PWM for the specific pins and tha dah… working

This entry was posted by Richard Garsthagen on November 8, 2012 at 11:00 pm, and is filed under Tools and Utilities. Follow any responses to this post through RSS 2.0. You can skip to the end and leave a response. Pinging is currently not allowed.

I myself started to get my Raspberry Pi started kit up and running yesterday, managed to get some leds to burn on the breadboard.

I would really like to know how you can control GPIO from the webserver. For now I use some Python service that reads from the MySQL database. I would also prefer to use PHP Extensions and skip Python.

Hello just wanted to give you a quick heads up and let you know a few of
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Well I am still making progress with my analog alarm/monitor box, but really still need to come up with a better name for it! If anyone has any suggestions, please shoot! I just finished the board design (I hope it is correct) and ordered a few boards, I should have them just after valentines. All the…

Is this a new trend? I hope so! I have been working on my analog hardware monitoring box for vSphere environments the last couple of weeks. This weekend I hope to finish writing my software so I can finally release a full working version. But I am not the only one experimenting with Arduino’s and…

As I received many positive reactions on my Analog Alarm Box to monitor your VMware vSphere environment, I decided for the first “finalized” product to not include the split-flip display, as I still need to work out a lot of things to be able to “mass” produce it. The slim box will have 4 analog…

As I am happy with the progress my little project is taking, I thought I would share with you all what I am working on. I like to make physical things and one of the things I have been developing is and old-school split-flap display (You know from those boards in old train stations). Some…